A Pilot Study on the Effects of Sweet Potato Petiole and Leaf Powder on Gut Microbiota and Aging-Related Biomarkers in an Aged Microminipig Model

Background/Objectives: Although many healthy foods are used for elderly humans, there are no suitable animal models to test them. We reared microminipigs (MMPs) for over 10 years, establishing aged MMP models. Using this aged preclinical model, we evaluated the effects of a polyphenol-rich diet without sacrificing the animals. Methods: A polyphenol-rich diet containing sweet potato petioles and leaves was administered to the aged MMPs daily for one month. Changes in fecal microbiota and aging-related cells in the peripheral blood before and after administration were assessed. Results: Administration of a diet containing sweet potato petiole and leaf resulted in increased abundance of the genera Muribaculaceae, Oscillibacter, and Desulfovibrio and a decreased abundance of the genus UCG-002 within the family Oscillospiraceae. Prediction of metabolic enzyme activity from microbiota composition identified 77 enzymes significantly altered after administration. KEGG Mapper analysis of these enzymes revealed their involvement in 27 pathways. Flow cytometry analysis of peripheral blood revealed no significant differences in the proportion of ß-galactosidase-positive cells in either group. In contrast, a significant increase in the number of Ki-67-positive cells was observed in some individuals in the treatment group. However, no significant differences in Ki-67 expression were detected after stimulation with anti-CD3/CD28 antibodies. Conclusions: We established an aged MMP model to evaluate the efficacy and safety of drugs and health foods in elderly humans. Using this model, sweet potato petioles and leaves were shown to have potential as candidate materials for future health food research.